Rotating inactive storage units in a distributed storage network

ABSTRACT

A method begins by a dispersed storage (DS) processing module of a dispersed storage network (DSN) obtaining status information from a set of distributed storage units (SUs) and determining that a plurality of the SUs are currently inactive. The method continues with the DS processing module selecting one or more inactive SUs for reactivation and issuing a request to change activation status to each. When a favorable response is received from the one more SUs, the method continues with the DDS processing module determining that encoded data slices (EDSs) stored in a first SU include errors and determining to rebuild the EDSs stored in the first SU that include one or more errors by issuing a request to change activation status to second SU that is currently inactive. Upon receiving a favorable response from the second SU, the EDSs with errors are rebuilt using EDSs from the second SU.

CROSS REFERENCE TO RELATED PATENTS

The present U.S. Utility patent application claims priority pursuant to 35 U.S.C. § 120, as a continuation-in-part to U.S. Utility patent application Ser. No. 15/425,128, entitled “DETECTION AND CORRECTION OF COPY ERRORS IN A DISTRIBUTED STORAGE NETWORK”, filed Feb. 6, 2017, which is a continuation of U.S. Utility patent application Ser. No. 14/320,547, entitled “UPDATING DE-DUPLICATION TRACKING DATA FOR A DISPERSED STORAGE NETWORK”, filed Jun. 30, 2014, issued as U.S. Pat. No. 9,661,074 on May 23, 2017, which claims priority pursuant to 35 U.S.C. § 119(e) to U.S. Provisional Application No. 61/871,833, entitled “PRIORITIZING DATA RETENTION IN A DISPERSED STORAGE NETWORK”, filed Aug. 29, 2013, all of which are hereby incorporated herein by reference in their entirety and made part of the present U.S. Utility patent application for all purposes.

BACKGROUND OF THE INVENTION Technical Field of the Invention

This invention relates generally to computer networks and more particularly to dispersed storage of data and distributed task processing of data.

Description of Related Art

Computing devices are known to communicate data, process data, and/or store data. Such computing devices range from wireless smart phones, laptops, tablets, personal computers (PC), work stations, and video game devices, to data centers that support millions of web searches, stock trades, or on-line purchases every day. In general, a computing device includes a central processing unit (CPU), a memory system, user input/output interfaces, peripheral device interfaces, and an interconnecting bus structure.

As is further known, a computer may effectively extend its CPU by using “cloud computing” to perform one or more computing functions (e.g., a service, an application, an algorithm, an arithmetic logic function, etc.) on behalf of the computer. Further, for large services, applications, and/or functions, cloud computing may be performed by multiple cloud computing resources in a distributed manner to improve the response time for completion of the service, application, and/or function. For example, Hadoop is an open source software framework that supports distributed applications enabling application execution by thousands of computers.

In addition to cloud computing, a computer may use “cloud storage” as part of its memory system. As is known, cloud storage enables a user, via its computer, to store files, applications, etc. on an Internet storage system. The Internet storage system may include a RAID (redundant array of independent disks) system and/or a dispersed storage system that uses an error correction scheme to encode data for storage.

BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWING(S)

FIG. 1 is a schematic block diagram of an embodiment of a distributed computing system in accordance with the present invention;

FIG. 2 is a schematic block diagram of an embodiment of a computing core in accordance with the present invention;

FIG. 3 is a diagram of an example of a distributed storage and task processing in accordance with the present invention;

FIG. 4 is a schematic block diagram of an embodiment of an outbound distributed storage and/or task (DST) processing in accordance with the present invention;

FIG. 5 is a logic diagram of an example of a method for outbound DST processing in accordance with the present invention;

FIG. 6 is a schematic block diagram of an embodiment of a dispersed error encoding in accordance with the present invention;

FIG. 7 is a diagram of an example of a segment processing of the dispersed error encoding in accordance with the present invention;

FIG. 8 is a diagram of an example of error encoding and slicing processing of the dispersed error encoding in accordance with the present invention;

FIG. 9 is a diagram of an example of grouping selection processing of the outbound DST processing in accordance with the present invention;

FIG. 10 is a diagram of an example of converting data into slice groups in accordance with the present invention;

FIG. 11A is a schematic block diagram of an embodiment of a dispersed storage network in accordance with the present invention;

FIG. 11B is a flowchart illustrating an example of activating a new dispersed storage network vault in accordance with the present invention;

FIG. 12A is a schematic block diagram of another embodiment of a distributed storage and task execution unit in accordance with the present invention;

FIG. 12B is a flowchart illustrating an example of detecting a processing activity anomaly in accordance with the present invention;

FIG. 13A is a schematic block diagram of another embodiment of a dispersed storage network in accordance with the present invention;

FIG. 13B is a flowchart illustrating an example of selecting active storage units in accordance with the present invention; and

FIG. 14 is a flowchart illustrating an example of enabling slice rebuilding in accordance with the present invention.

DETAILED DESCRIPTION OF THE INVENTION

FIG. 1 is a schematic block diagram of an embodiment of a distributed computing system 10 that includes a user device 12 and/or a user device 14, a distributed storage and/or task (DST) processing unit 16, a distributed storage and/or task network (DSTN) managing unit 18, a DST integrity processing unit 20, and a distributed storage and/or task network (DSTN) module 22. The components of the distributed computing system 10 are coupled via a network 24, which may include one or more wireless and/or wire lined communication systems; one or more private intranet systems and/or public internet systems; and/or one or more local area networks (LAN) and/or wide area networks (WAN).

The DSTN module 22 includes a plurality of distributed storage and/or task (DST) execution units 36 that may be located at geographically different sites (e.g., one in Chicago, one in Milwaukee, etc.). Each of the DST execution units is operable to store dispersed error encoded data and/or to execute, in a distributed manner, one or more tasks on data. The tasks may be a simple function (e.g., a mathematical function, a logic function, an identify function, a find function, a search engine function, a replace function, etc.), a complex function (e.g., compression, human and/or computer language translation, text-to-voice conversion, voice-to-text conversion, etc.), multiple simple and/or complex functions, one or more algorithms, one or more applications, etc.

Each of the user devices 12-14, the DST processing unit 16, the DSTN managing unit 18, and the DST integrity processing unit 20 include a computing core 26 and may be a portable computing device and/or a fixed computing device. A portable computing device may be a social networking device, a gaming device, a cell phone, a smart phone, a personal digital assistant, a digital music player, a digital video player, a laptop computer, a handheld computer, a tablet, a video game controller, and/or any other portable device that includes a computing core. A fixed computing device may be a personal computer (PC), a computer server, a cable set-top box, a satellite receiver, a television set, a printer, a fax machine, home entertainment equipment, a video game console, and/or any type of home or office computing equipment. User device 12 and DST processing unit 16 are configured to include a DST client module 34.

With respect to interfaces, each interface 30, 32, and 33 includes software and/or hardware to support one or more communication links via the network 24 indirectly and/or directly. For example, interfaces 30 support a communication link (e.g., wired, wireless, direct, via a LAN, via the network 24, etc.) between user device 14 and the DST processing unit 16. As another example, interface 32 supports communication links (e.g., a wired connection, a wireless connection, a LAN connection, and/or any other type of connection to/from the network 24) between user device 12 and the DSTN module 22 and between the DST processing unit 16 and the DSTN module 22. As yet another example, interface 33 supports a communication link for each of the DSTN managing unit 18 and DST integrity processing unit 20 to the network 24.

The distributed computing system 10 is operable to support dispersed storage (DS) error encoded data storage and retrieval, to support distributed task processing on received data, and/or to support distributed task processing on stored data. In general and with respect to DS error encoded data storage and retrieval, the distributed computing system 10 supports three primary operations: storage management, data storage and retrieval (an example of which will be discussed with reference to FIGS. 20-26), and data storage integrity verification. In accordance with these three primary functions, data can be encoded, distributedly stored in physically different locations, and subsequently retrieved in a reliable and secure manner. Such a system is tolerant of a significant number of failures (e.g., up to a failure level, which may be greater than or equal to a pillar width minus a decode threshold minus one) that may result from individual storage device failures and/or network equipment failures without loss of data and without the need for a redundant or backup copy. Further, the system allows the data to be stored for an indefinite period of time without data loss and does so in a secure manner (e.g., the system is very resistant to attempts at hacking the data).

The second primary function (i.e., distributed data storage and retrieval) begins and ends with a user device 12-14. For instance, if a second type of user device 14 has data 40 to store in the DSTN module 22, it sends the data 40 to the DST processing unit 16 via its interface 30. The interface 30 functions to mimic a conventional operating system (OS) file system interface (e.g., network file system (NFS), flash file system (FFS), disk file system (DFS), file transfer protocol (FTP), web-based distributed authoring and versioning (WebDAV), etc.) and/or a block memory interface (e.g., small computer system interface (SCSI), internet small computer system interface (iSCSI), etc.). In addition, the interface 30 may attach a user identification code (ID) to the data 40.

To support storage management, the DSTN managing unit 18 performs DS management services. One such DS management service includes the DSTN managing unit 18 establishing distributed data storage parameters (e.g., vault creation, distributed storage parameters, security parameters, billing information, user profile information, etc.) for a user device 12-14 individually or as part of a group of user devices. For example, the DSTN managing unit 18 coordinates creation of a vault (e.g., a virtual memory block) within memory of the DSTN module 22 for a user device, a group of devices, or for public access and establishes per vault dispersed storage (DS) error encoding parameters for a vault. The DSTN managing unit 18 may facilitate storage of DS error encoding parameters for each vault of a plurality of vaults by updating registry information for the distributed computing system 10. The facilitating includes storing updated registry information in one or more of the DSTN module 22, the user device 12, the DST processing unit 16, and the DST integrity processing unit 20.

The DS error encoding parameters (e.g. or dispersed storage error coding parameters) include data segmenting information (e.g., how many segments data (e.g., a file, a group of files, a data block, etc.) is divided into), segment security information (e.g., per segment encryption, compression, integrity checksum, etc.), error coding information (e.g., pillar width, decode threshold, read threshold, write threshold, etc.), slicing information (e.g., the number of encoded data slices that will be created for each data segment); and slice security information (e.g., per encoded data slice encryption, compression, integrity checksum, etc.).

The DSTN managing module 18 creates and stores user profile information (e.g., an access control list (ACL)) in local memory and/or within memory of the DSTN module 22. The user profile information includes authentication information, permissions, and/or the security parameters. The security parameters may include encryption/decryption scheme, one or more encryption keys, key generation scheme, and/or data encoding/decoding scheme.

The DSTN managing unit 18 creates billing information for a particular user, a user group, a vault access, public vault access, etc. For instance, the DSTN managing unit 18 tracks the number of times a user accesses a private vault and/or public vaults, which can be used to generate a per-access billing information. In another instance, the DSTN managing unit 18 tracks the amount of data stored and/or retrieved by a user device and/or a user group, which can be used to generate a per-data-amount billing information.

Another DS management service includes the DSTN managing unit 18 performing network operations, network administration, and/or network maintenance. Network operations include authenticating user data allocation requests (e.g., read and/or write requests), managing creation of vaults, establishing authentication credentials for user devices, adding/deleting components (e.g., user devices, DST execution units, and/or DST processing units) from the distributed computing system 10, and/or establishing authentication credentials for DST execution units 36. Network administration includes monitoring devices and/or units for failures, maintaining vault information, determining device and/or unit activation status, determining device and/or unit loading, and/or determining any other system level operation that affects the performance level of the system 10. Network maintenance includes facilitating replacing, upgrading, repairing, and/or expanding a device and/or unit of the system 10.

To support data storage integrity verification within the distributed computing system 10, the DST integrity processing unit 20 performs rebuilding of ‘bad’ or missing encoded data slices. At a high level, the DST integrity processing unit 20 performs rebuilding by periodically attempting to retrieve/list encoded data slices, and/or slice names of the encoded data slices, from the DSTN module 22. For retrieved encoded slices, they are checked for errors due to data corruption, outdated version, etc. If a slice includes an error, it is flagged as a ‘bad’ slice. For encoded data slices that were not received and/or not listed, they are flagged as missing slices. Bad and/or missing slices are subsequently rebuilt using other retrieved encoded data slices that are deemed to be good slices to produce rebuilt slices. The rebuilt slices are stored in memory of the DSTN module 22. Note that the DST integrity processing unit 20 may be a separate unit as shown, it may be included in the DSTN module 22, it may be included in the DST processing unit 16, and/or distributed among the DST execution units 36.

To support distributed task processing on received data, the distributed computing system 10 has two primary operations: DST (distributed storage and/or task processing) management and DST execution on received data (an example of which will be discussed with reference to FIGS. 3-19). With respect to the storage portion of the DST management, the DSTN managing unit 18 functions as previously described. With respect to the tasking processing of the DST management, the DSTN managing unit 18 performs distributed task processing (DTP) management services. One such DTP management service includes the DSTN managing unit 18 establishing DTP parameters (e.g., user-vault affiliation information, billing information, user-task information, etc.) for a user device 12-14 individually or as part of a group of user devices.

Another DTP management service includes the DSTN managing unit 18 performing DTP network operations, network administration (which is essentially the same as described above), and/or network maintenance (which is essentially the same as described above). Network operations include, but are not limited to, authenticating user task processing requests (e.g., valid request, valid user, etc.), authenticating results and/or partial results, establishing DTP authentication credentials for user devices, adding/deleting components (e.g., user devices, DST execution units, and/or DST processing units) from the distributed computing system, and/or establishing DTP authentication credentials for DST execution units.

To support distributed task processing on stored data, the distributed computing system 10 has two primary operations: DST (distributed storage and/or task) management and DST execution on stored data. With respect to the DST execution on stored data, if the second type of user device 14 has a task request 38 for execution by the DSTN module 22, it sends the task request 38 to the DST processing unit 16 via its interface 30. An example of DST execution on stored data will be discussed in greater detail with reference to FIGS. 27-39. With respect to the DST management, it is substantially similar to the DST management to support distributed task processing on received data.

FIG. 2 is a schematic block diagram of an embodiment of a computing core 26 that includes a processing module 50, a memory controller 52, main memory 54, a video graphics processing unit 55, an input/output (TO) controller 56, a peripheral component interconnect (PCI) interface 58, an IO interface module 60, at least one IO device interface module 62, a read only memory (ROM) basic input output system (BIOS) 64, and one or more memory interface modules. The one or more memory interface module(s) includes one or more of a universal serial bus (USB) interface module 66, a host bus adapter (HBA) interface module 68, a network interface module 70, a flash interface module 72, a hard drive interface module 74, and a DSTN interface module 76.

The DSTN interface module 76 functions to mimic a conventional operating system (OS) file system interface (e.g., network file system (NFS), flash file system (FFS), disk file system (DFS), file transfer protocol (FTP), web-based distributed authoring and versioning (WebDAV), etc.) and/or a block memory interface (e.g., small computer system interface (SCSI), internet small computer system interface (iSCSI), etc.). The DSTN interface module 76 and/or the network interface module 70 may function as the interface 30 of the user device 14 of FIG. 1. Further note that the IO device interface module 62 and/or the memory interface modules may be collectively or individually referred to as IO ports.

FIG. 3 is a diagram of an example of the distributed computing system performing a distributed storage and task processing operation. The distributed computing system includes a DST (distributed storage and/or task) client module 34 (which may be in user device 14 and/or in DST processing unit 16 of FIG. 1), a network 24, a plurality of DST execution units 1-n that includes two or more DST execution units 36 of FIG. 1 (which form at least a portion of DSTN module 22 of FIG. 1), a DST managing module (not shown), and a DST integrity verification module (not shown). The DST client module 34 includes an outbound DST processing section 80 and an inbound DST processing section 82. Each of the DST execution units 1-n includes a controller 86, a processing module 84, memory 88, a DT (distributed task) execution module 90, and a DST client module 34.

In an example of operation, the DST client module 34 receives data 92 and one or more tasks 94 to be performed upon the data 92. The data 92 may be of any size and of any content, where, due to the size (e.g., greater than a few Terabytes), the content (e.g., secure data, etc.), and/or task(s) (e.g., MIPS intensive), distributed processing of the task(s) on the data is desired. For example, the data 92 may be one or more digital books, a copy of a company's emails, a large-scale Internet search, a video security file, one or more entertainment video files (e.g., television programs, movies, etc.), data files, and/or any other large amount of data (e.g., greater than a few Terabytes).

Within the DST client module 34, the outbound DST processing section 80 receives the data 92 and the task(s) 94. The outbound DST processing section 80 processes the data 92 to produce slice groupings 96. As an example of such processing, the outbound DST processing section 80 partitions the data 92 into a plurality of data partitions. For each data partition, the outbound DST processing section 80 dispersed storage (DS) error encodes the data partition to produce encoded data slices and groups the encoded data slices into a slice grouping 96. In addition, the outbound DST processing section 80 partitions the task 94 into partial tasks 98, where the number of partial tasks 98 may correspond to the number of slice groupings 96.

The outbound DST processing section 80 then sends, via the network 24, the slice groupings 96 and the partial tasks 98 to the DST execution units 1-n of the DSTN module 22 of FIG. 1. For example, the outbound DST processing section 80 sends slice group 1 and partial task 1 to DST execution unit 1. As another example, the outbound DST processing section 80 sends slice group #n and partial task #n to DST execution unit #n.

Each DST execution unit performs its partial task 98 upon its slice group 96 to produce partial results 102. For example, DST execution unit #1 performs partial task #1 on slice group #1 to produce a partial result #1, for results. As a more specific example, slice group #1 corresponds to a data partition of a series of digital books and the partial task #1 corresponds to searching for specific phrases, recording where the phrase is found, and establishing a phrase count. In this more specific example, the partial result #1 includes information as to where the phrase was found and includes the phrase count.

Upon completion of generating their respective partial results 102, the DST execution units send, via the network 24, their partial results 102 to the inbound DST processing section 82 of the DST client module 34. The inbound DST processing section 82 processes the received partial results 102 to produce a result 104. Continuing with the specific example of the preceding paragraph, the inbound DST processing section 82 combines the phrase count from each of the DST execution units 36 to produce a total phrase count. In addition, the inbound DST processing section 82 combines the ‘where the phrase was found’ information from each of the DST execution units 36 within their respective data partitions to produce ‘where the phrase was found’ information for the series of digital books.

In another example of operation, the DST client module 34 requests retrieval of stored data within the memory of the DST execution units 36 (e.g., memory of the DSTN module). In this example, the task 94 is retrieve data stored in the memory of the DSTN module. Accordingly, the outbound DST processing section 80 converts the task 94 into a plurality of partial tasks 98 and sends the partial tasks 98 to the respective DST execution units 1-n.

In response to the partial task 98 of retrieving stored data, a DST execution unit 36 identifies the corresponding encoded data slices 100 and retrieves them. For example, DST execution unit #1 receives partial task #1 and retrieves, in response thereto, retrieved slices #1. The DST execution units 36 send their respective retrieved slices 100 to the inbound DST processing section 82 via the network 24.

The inbound DST processing section 82 converts the retrieved slices 100 into data 92. For example, the inbound DST processing section 82 de-groups the retrieved slices 100 to produce encoded slices per data partition. The inbound DST processing section 82 then DS error decodes the encoded slices per data partition to produce data partitions. The inbound DST processing section 82 de-partitions the data partitions to recapture the data 92.

FIG. 4 is a schematic block diagram of an embodiment of an outbound distributed storage and/or task (DST) processing section 80 of a DST client module 34 FIG. 1 coupled to a DSTN module 22 of a FIG. 1 (e.g., a plurality of n DST execution units 36) via a network 24. The outbound DST processing section 80 includes a data partitioning module 110, a dispersed storage (DS) error encoding module 112, a grouping selector module 114, a control module 116, and a distributed task control module 118.

In an example of operation, the data partitioning module 110 partitions data 92 into a plurality of data partitions 120. The number of partitions and the size of the partitions may be selected by the control module 116 via control 160 based on the data 92 (e.g., its size, its content, etc.), a corresponding task 94 to be performed (e.g., simple, complex, single step, multiple steps, etc.), DS encoding parameters (e.g., pillar width, decode threshold, write threshold, segment security parameters, slice security parameters, etc.), capabilities of the DST execution units 36 (e.g., processing resources, availability of processing recourses, etc.), and/or as may be inputted by a user, system administrator, or other operator (human or automated). For example, the data partitioning module 110 partitions the data 92 (e.g., 100 Terabytes) into 100,000 data segments, each being 1 Gigabyte in size. Alternatively, the data partitioning module 110 partitions the data 92 into a plurality of data segments, where some of data segments are of a different size, are of the same size, or a combination thereof.

The DS error encoding module 112 receives the data partitions 120 in a serial manner, a parallel manner, and/or a combination thereof. For each data partition 120, the DS error encoding module 112 DS error encodes the data partition 120 in accordance with control information 160 from the control module 116 to produce encoded data slices 122. The DS error encoding includes segmenting the data partition into data segments, segment security processing (e.g., encryption, compression, watermarking, integrity check (e.g., CRC), etc.), error encoding, slicing, and/or per slice security processing (e.g., encryption, compression, watermarking, integrity check (e.g., CRC), etc.). The control information 160 indicates which steps of the DS error encoding are active for a given data partition and, for active steps, indicates the parameters for the step. For example, the control information 160 indicates that the error encoding is active and includes error encoding parameters (e.g., pillar width, decode threshold, write threshold, read threshold, type of error encoding, etc.).

The grouping selector module 114 groups the encoded slices 122 of a data partition into a set of slice groupings 96. The number of slice groupings corresponds to the number of DST execution units 36 identified for a particular task 94. For example, if five DST execution units 36 are identified for the particular task 94, the group selecting module groups the encoded slices 122 of a data partition into five slice groupings 96. The grouping selector module 114 outputs the slice groupings 96 to the corresponding DST execution units 36 via the network 24.

The distributed task control module 118 receives the task 94 and converts the task 94 into a set of partial tasks 98. For example, the distributed task control module 118 receives a task to find where in the data (e.g., a series of books) a phrase occurs and a total count of the phrase usage in the data. In this example, the distributed task control module 118 replicates the task 94 for each DST execution unit 36 to produce the partial tasks 98. In another example, the distributed task control module 118 receives a task to find where in the data a first phrase occurs, where in the data a second phrase occurs, and a total count for each phrase usage in the data. In this example, the distributed task control module 118 generates a first set of partial tasks 98 for finding and counting the first phase and a second set of partial tasks for finding and counting the second phrase. The distributed task control module 118 sends respective first and/or second partial tasks 98 to each DST execution unit 36.

FIG. 5 is a logic diagram of an example of a method for outbound distributed storage and task (DST) processing that begins at step 126 where a DST client module receives data and one or more corresponding tasks. The method continues at step 128 where the DST client module determines a number of DST units to support the task for one or more data partitions. For example, the DST client module may determine the number of DST units to support the task based on the size of the data, the requested task, the content of the data, a predetermined number (e.g., user indicated, system administrator determined, etc.), available DST units, capability of the DST units, and/or any other factor regarding distributed task processing of the data. The DST client module may select the same DST units for each data partition, may select different DST units for the data partitions, or a combination thereof.

The method continues at step 130 where the DST client module determines processing parameters of the data based on the number of DST units selected for distributed task processing. The processing parameters include data partitioning information, DS encoding parameters, and/or slice grouping information. The data partitioning information includes a number of data partitions, size of each data partition, and/or organization of the data partitions (e.g., number of data blocks in a partition, the size of the data blocks, and arrangement of the data blocks). The DS encoding parameters include segmenting information, segment security information, error encoding information (e.g., dispersed storage error encoding function parameters including one or more of pillar width, decode threshold, write threshold, read threshold, generator matrix), slicing information, and/or per slice security information. The slice grouping information includes information regarding how to arrange the encoded data slices into groups for the selected DST units. As a specific example, if the DST client module determines that five DST units are needed to support the task, then it determines that the error encoding parameters include a pillar width of five and a decode threshold of three.

The method continues at step 132 where the DST client module determines task partitioning information (e.g., how to partition the tasks) based on the selected DST units and data processing parameters. The data processing parameters include the processing parameters and DST unit capability information. The DST unit capability information includes the number of DT (distributed task) execution units, execution capabilities of each DT execution unit (e.g., MIPS capabilities, processing resources (e.g., quantity and capability of microprocessors, CPUs, digital signal processors, co-processor, microcontrollers, arithmetic logic circuitry, and/or and the other analog and/or digital processing circuitry), availability of the processing resources, memory information (e.g., type, size, availability, etc.)), and/or any information germane to executing one or more tasks.

The method continues at step 134 where the DST client module processes the data in accordance with the processing parameters to produce slice groupings. The method continues at step 136 where the DST client module partitions the task based on the task partitioning information to produce a set of partial tasks. The method continues at step 138 where the DST client module sends the slice groupings and the corresponding partial tasks to respective DST units.

FIG. 6 is a schematic block diagram of an embodiment of the dispersed storage (DS) error encoding module 112 of an outbound distributed storage and task (DST) processing section. The DS error encoding module 112 includes a segment processing module 142, a segment security processing module 144, an error encoding module 146, a slicing module 148, and a per slice security processing module 150. Each of these modules is coupled to a control module 116 to receive control information 160 therefrom.

In an example of operation, the segment processing module 142 receives a data partition 120 from a data partitioning module and receives segmenting information as the control information 160 from the control module 116. The segmenting information indicates how the segment processing module 142 is to segment the data partition 120. For example, the segmenting information indicates how many rows to segment the data based on a decode threshold of an error encoding scheme, indicates how many columns to segment the data into based on a number and size of data blocks within the data partition 120, and indicates how many columns to include in a data segment 152. The segment processing module 142 segments the data 120 into data segments 152 in accordance with the segmenting information.

The segment security processing module 144, when enabled by the control module 116, secures the data segments 152 based on segment security information received as control information 160 from the control module 116. The segment security information includes data compression, encryption, watermarking, integrity check (e.g., cyclic redundancy check (CRC), etc.), and/or any other type of digital security. For example, when the segment security processing module 144 is enabled, it may compress a data segment 152, encrypt the compressed data segment, and generate a CRC value for the encrypted data segment to produce a secure data segment 154. When the segment security processing module 144 is not enabled, it passes the data segments 152 to the error encoding module 146 or is bypassed such that the data segments 152 are provided to the error encoding module 146.

The error encoding module 146 encodes the secure data segments 154 in accordance with error correction encoding parameters received as control information 160 from the control module 116. The error correction encoding parameters (e.g., also referred to as dispersed storage error coding parameters) include identifying an error correction encoding scheme (e.g., forward error correction algorithm, a Reed-Solomon based algorithm, an online coding algorithm, an information dispersal algorithm, etc.), a pillar width, a decode threshold, a read threshold, a write threshold, etc. For example, the error correction encoding parameters identify a specific error correction encoding scheme, specifies a pillar width of five, and specifies a decode threshold of three. From these parameters, the error encoding module 146 encodes a data segment 154 to produce an encoded data segment 156.

The slicing module 148 slices the encoded data segment 156 in accordance with the pillar width of the error correction encoding parameters received as control information 160. For example, if the pillar width is five, the slicing module 148 slices an encoded data segment 156 into a set of five encoded data slices. As such, for a plurality of encoded data segments 156 for a given data partition, the slicing module outputs a plurality of sets of encoded data slices 158.

The per slice security processing module 150, when enabled by the control module 116, secures each encoded data slice 158 based on slice security information received as control information 160 from the control module 116. The slice security information includes data compression, encryption, watermarking, integrity check (e.g., CRC, etc.), and/or any other type of digital security. For example, when the per slice security processing module 150 is enabled, it compresses an encoded data slice 158, encrypts the compressed encoded data slice, and generates a CRC value for the encrypted encoded data slice to produce a secure encoded data slice 122. When the per slice security processing module 150 is not enabled, it passes the encoded data slices 158 or is bypassed such that the encoded data slices 158 are the output of the DS error encoding module 112. Note that the control module 116 may be omitted and each module stores its own parameters.

FIG. 7 is a diagram of an example of a segment processing of a dispersed storage (DS) error encoding module. In this example, a segment processing module 142 receives a data partition 120 that includes 45 data blocks (e.g., d1-d45), receives segmenting information (i.e., control information 160) from a control module, and segments the data partition 120 in accordance with the control information 160 to produce data segments 152. Each data block may be of the same size as other data blocks or of a different size. In addition, the size of each data block may be a few bytes to megabytes of data. As previously mentioned, the segmenting information indicates how many rows to segment the data partition into, indicates how many columns to segment the data partition into, and indicates how many columns to include in a data segment.

In this example, the decode threshold of the error encoding scheme is three; as such the number of rows to divide the data partition into is three. The number of columns for each row is set to 15, which is based on the number and size of data blocks. The data blocks of the data partition are arranged in rows and columns in a sequential order (i.e., the first row includes the first 15 data blocks; the second row includes the second 15 data blocks; and the third row includes the last 15 data blocks).

With the data blocks arranged into the desired sequential order, they are divided into data segments based on the segmenting information. In this example, the data partition is divided into 8 data segments; the first 7 include 2 columns of three rows and the last includes 1 column of three rows. Note that the first row of the 8 data segments is in sequential order of the first 15 data blocks; the second row of the 8 data segments in sequential order of the second 15 data blocks; and the third row of the 8 data segments in sequential order of the last 15 data blocks. Note that the number of data blocks, the grouping of the data blocks into segments, and size of the data blocks may vary to accommodate the desired distributed task processing function.

FIG. 8 is a diagram of an example of error encoding and slicing processing of the dispersed error encoding processing the data segments of FIG. 7. In this example, data segment 1 includes 3 rows with each row being treated as one word for encoding. As such, data segment 1 includes three words for encoding: word 1 including data blocks d1 and d2, word 2 including data blocks d16 and d17, and word 3 including data blocks d31 and d32. Each of data segments 2-7 includes three words where each word includes two data blocks. Data segment 8 includes three words where each word includes a single data block (e.g., d15, d30, and d45).

In operation, an error encoding module 146 and a slicing module 148 convert each data segment into a set of encoded data slices in accordance with error correction encoding parameters as control information 160. More specifically, when the error correction encoding parameters indicate a unity matrix Reed-Solomon based encoding algorithm, 5 pillars, and decode threshold of 3, the first three encoded data slices of the set of encoded data slices for a data segment are substantially similar to the corresponding word of the data segment. For instance, when the unity matrix Reed-Solomon based encoding algorithm is applied to data segment 1, the content of the first encoded data slice (DS1_d1&2) of the first set of encoded data slices (e.g., corresponding to data segment 1) is substantially similar to content of the first word (e.g., d1 & d2); the content of the second encoded data slice (DS1_d16&17) of the first set of encoded data slices is substantially similar to content of the second word (e.g., d16 & d17); and the content of the third encoded data slice (DS1_d31&32) of the first set of encoded data slices is substantially similar to content of the third word (e.g., d31 & d32).

The content of the fourth and fifth encoded data slices (e.g., ES1_1 and ES1_2) of the first set of encoded data slices include error correction data based on the first-third words of the first data segment. With such an encoding and slicing scheme, retrieving any three of the five encoded data slices allows the data segment to be accurately reconstructed.

The encoding and slices of data segments 2-7 yield sets of encoded data slices similar to the set of encoded data slices of data segment 1. For instance, the content of the first encoded data slice (DS2_d3&4) of the second set of encoded data slices (e.g., corresponding to data segment 2) is substantially similar to content of the first word (e.g., d3 & d4); the content of the second encoded data slice (DS2_d18&19) of the second set of encoded data slices is substantially similar to content of the second word (e.g., d18 & d19); and the content of the third encoded data slice (DS2_d33&34) of the second set of encoded data slices is substantially similar to content of the third word (e.g., d33 & d34). The content of the fourth and fifth encoded data slices (e.g., ES1_1 and ES1_2) of the second set of encoded data slices includes error correction data based on the first-third words of the second data segment.

FIG. 9 is a diagram of an example of grouping selection processing of an outbound distributed storage and task (DST) processing in accordance with group selection information as control information 160 from a control module. Encoded slices for data partition 122 are grouped in accordance with the control information 160 to produce slice groupings 96. In this example, a grouping selection module 114 organizes the encoded data slices into five slice groupings (e.g., one for each DST execution unit of a distributed storage and task network (DSTN) module). As a specific example, the grouping selection module 114 creates a first slice grouping for a DST execution unit #1, which includes first encoded slices of each of the sets of encoded slices. As such, the first DST execution unit receives encoded data slices corresponding to data blocks 1-15 (e.g., encoded data slices of contiguous data).

The grouping selection module 114 also creates a second slice grouping for a DST execution unit #2, which includes second encoded slices of each of the sets of encoded slices. As such, the second DST execution unit receives encoded data slices corresponding to data blocks 16-30. The grouping selection module 114 further creates a third slice grouping for DST execution unit #3, which includes third encoded slices of each of the sets of encoded slices. As such, the third DST execution unit receives encoded data slices corresponding to data blocks 31-45.

The grouping selection module 114 creates a fourth slice grouping for DST execution unit #4, which includes fourth encoded slices of each of the sets of encoded slices. As such, the fourth DST execution unit receives encoded data slices corresponding to first error encoding information (e.g., encoded data slices of error coding (EC) data). The grouping selection module 114 further creates a fifth slice grouping for DST execution unit #5, which includes fifth encoded slices of each of the sets of encoded slices. As such, the fifth DST execution unit receives encoded data slices corresponding to second error encoding information.

FIG. 10 is a diagram of an example of converting data 92 into slice groups that expands on the preceding figures. As shown, the data 92 is partitioned in accordance with a partitioning function 164 into a plurality of data partitions (1-x, where x is an integer greater than 4). Each data partition (or chunkset of data) is encoded and grouped into slice groupings as previously discussed by an encoding and grouping function 166. For a given data partition, the slice groupings are sent to distributed storage and task (DST) execution units. From data partition to data partition, the ordering of the slice groupings to the DST execution units may vary.

For example, the slice groupings of data partition #1 is sent to the DST execution units such that the first DST execution receives first encoded data slices of each of the sets of encoded data slices, which corresponds to a first continuous data chunk of the first data partition (e.g., refer to FIG. 9), a second DST execution receives second encoded data slices of each of the sets of encoded data slices, which corresponds to a second continuous data chunk of the first data partition, etc.

For the second data partition, the slice groupings may be sent to the DST execution units in a different order than it was done for the first data partition. For instance, the first slice grouping of the second data partition (e.g., slice group 2_1) is sent to the second DST execution unit; the second slice grouping of the second data partition (e.g., slice group 2_2) is sent to the third DST execution unit; the third slice grouping of the second data partition (e.g., slice group 2_3) is sent to the fourth DST execution unit; the fourth slice grouping of the second data partition (e.g., slice group 2_4, which includes first error coding information) is sent to the fifth DST execution unit; and the fifth slice grouping of the second data partition (e.g., slice group 2_5, which includes second error coding information) is sent to the first DST execution unit.

The pattern of sending the slice groupings to the set of DST execution units may vary in a predicted pattern, a random pattern, and/or a combination thereof from data partition to data partition. In addition, from data partition to data partition, the set of DST execution units may change. For example, for the first data partition, DST execution units 1-5 may be used; for the second data partition, DST execution units 6-10 may be used; for the third data partition, DST execution units 3-7 may be used; etc. As is also shown, the task is divided into partial tasks that are sent to the DST execution units in conjunction with the slice groupings of the data partitions.

FIG. 11A is a schematic block diagram of another embodiment of a dispersed storage network (DSN) that includes the distributed storage and task (DST) processing unit 16 of FIG. 1 and the distributed storage and task network (DSTN) managing unit 18 of FIG. 1. The DSN functions to provision a vault. In an example of operation, the DSTN managing unit 18 generates a plurality of vault templates 430 based on one or more of a manager input, a previous vault, DSN network configuration information, DSN capabilities, a vault list, and an expected vault list. As a specific example, the DSTN managing unit 18 updates a previous vault template based on the DSN network configuration information to produce a first vault template.

Each vault template 430 includes a plurality of fields, where each field includes one or more entries. The plurality of fields includes a template name field 428 that includes a name entry for the template, a width field 432 that includes a width entry (e.g., dispersed storage pillar width parameter), a decode threshold field 434 that includes a decode threshold entry (e.g., dispersed storage decode threshold parameter), a storage pools field 436 that includes entries of identifiers of storage units of one or more storage pools, a storage quotas field 438 that includes entries of storage quota maximums associated with one or more users of the vault, a codecs field 440 that includes one or more entries of codecs utilized in dispersed storage error coding (e.g., a compression algorithm identifier, a encoding algorithm identifier, a integrity check algorithm identifier, etc.), a DST processing units field 442 that includes entries of identifiers of one or more DST processing units, and initial vault access control list (ACL) field 444 that includes one or more entries of access control information (e.g., permissions), and another vault information field 446 that includes one or more other vault information entries (e.g., any other common vault information required to support operation of the vault).

The operational example continues where the DSTN managing unit 18 receives a vault provisioning request 420 from a device (e.g., the DST processing unit 16) of the DSN, where the request 420 includes a vault name 426 (e.g., a new vault name) and a template name 428. The DSTN managing unit 18 verifies that the device is authorized to request provisioning of a vault (e.g., verifying with an access control list). When verified, the DSTN managing unit 18 obtains a vault template 430 that corresponds to the template name 428 of the vault provisioning request 420 (e.g., match template name entry of the vault template to the template name received in the vault provisioning request).

The DSTN managing unit 18 generates a new vault using the vault template by signing the vault name 426 of the vault provisioning request 420 and updating an access control list field 444 in accordance with the initial vault access control list and identifier of the device. As a specific example, the DSTN managing unit 18 enables the DST processing unit 16 to fully utilize and modify the vault as indicated in the ACL of the vault. The DSTN managing unit 18 activates the new vault. As a specific example, the DSTN managing unit 18 stores the new vault in a registry and publishes the registry to devices of the DSN as a registry publication 424. The DSTN managing unit 18 issues a vault provisioning response 422 to the device, where the response includes an indicator that the new vault of the vault name has been activated.

FIG. 11B is a flowchart illustrating an example of activating a new dispersed storage network vault. The method continues at step 448 where a processing module (e.g., of a distributed storage and task network (DSTN) managing unit) generates a plurality of vault templates. The method continues at step 450 where the processing module receives a vault provisioning request from a device of a dispersed storage network (DSN), where the vault provisioning request includes a vault name and a vault template name. The method continues at step 452 where the processing module verifies that the device is authorized to request a vault provisioning. As a specific example, the processing module accesses a current access control list of current registry information to determine whether the device has been assigned rights to request the vault provisioning.

When favorably authorized, the method continues at step 454 where the processing module retrieves a vault template of the plurality of all templates, where the vault template is associated with the vault template name. The method continues at step 456 where the processing module generates a new vault using the vault template to include assigning the vault name to the new vault. The generating further includes updating an access control list field of the new vault in accordance with the initial vault access control list and an identifier of the device. The method continues at step 458 where the processing module activates the new vault. The method continues at step 460 where the processing module issues a vault provisioning response to the device, where the response includes one or more of the vault name, an indicator that the new vault has been activated, and a plurality of entries of the new vault.

FIG. 12A is a schematic block diagram of another embodiment of a distributed storage and task (DST) execution unit 36 of FIG. 11. The DST execution unit 36 includes a variety of devices including the interface 169, a plurality of memories 88, the controller 86, a plurality of distributed task (DT) execution modules 90, and a plurality of DST client modules 34 of FIG. 11. The DST execution unit 36 further includes a power distribution module 462 and an anomaly detection module 464. The DST execution unit 36 functions to detect an anomaly associated with operation and control of the variety of devices as the variety of devices process partial task requests 98 to provide one or more of results 104, partial results 102, sub-slice groupings 170, and sub-partial task 172; store slices 96; and recover slices 100. The controller 86 controls the variety of devices. For example, the controller 86 issues a memory control 174 to control the plurality of memories 88. As another example, the controller 86 issues a task control 480 to control the plurality of DT execution modules 90. As yet another example, the controller 86 issues a DST control 482 to control the plurality of DST client modules 34.

The controller 86 monitors the operation of the variety devices and generates activity information 476 which includes, for each device of the DST execution unit 36, an identifier of the device, and an activity indicator by time. The activity information 476 further includes activity of the DST execution unit 36 (e.g., processing a partial task 98, storing a slice 96, retrieving a slice 100, etc.). As a specific example, the controller 86 indicates that a first memory 88 performs a series of write operations in response to a slice access request received by the DST execution unit 36 during a first timeframe and the first memory 88 is idle during a second timeframe. As another specific example, the controller 86 indicates that a first DT execution module 90 processed a partial task in response to a partial task execution request 98 during the first timeframe and was idle during the second timeframe. As yet another specific example, the controller 86 indicates that a second DST client module 34 and a third DST client module 34 where both idle during the first and second timeframes.

The power distribution module 462 receives input power 466, via the interface 169, and provides power to devices of the DST execution unit 36. As a specific example, the power distribution module 462 provides memory power 468 to the plurality of memories 88, DT power 470 to the plurality of DT execution modules 90, and DST power 472 to the plurality of DST client modules 34. The power distribution module 462 determines power utilization (e.g., over time as associated with a representation of time) of each device of each of the pluralities of memories 88, DT execution modules 90, and the DST client modules 34. As a specific example, the power distribution module 462 determines power utilization of the first memory 88 to be 100 milliamps (mA) during the first timeframe and 25 mA during the second timeframe. As another specific example, the power distribution module 462 determines power utilization of the first DT execution module 90 of 75 mA during the first timeframe and 10 mA during the second timeframe. As yet another specific example, the power distribution module 462 determines power utilization of the second DST client module 34 of 110 mA during the first and second timeframes and power utilization of the third DST client module 34 of 5 mA during the first and second timeframes.

The power distribution module 462 generates power usage information 474 based on the determined power utilization. The power usage information 474 includes, for each device of the DST execution unit 36, an identifier of the device, and a power utilization level of the device by time. The power distribution module 462 sends the power usage information to the anomaly detection module 464.

In an example of detecting the anomaly, the anomaly detection module 464 receives the activity information 476 and the power usage information 474. The anomaly detection module 464 stores the activity information 476 and the power usage information 474 to include common time references. The anomaly detection module 464 analyzes the activity information 476 and the power usage information 474 by common time frames of the common time references to produce trend information. The anomaly detection module 464 stores the trend information, which includes a correlation of the activity information 476 and the power usage information 474 over time. For example, the trend information indicates that the first memory device 88 utilizes 100 mA to perform the series of write operations during the first timeframe and utilizes 25 mA when idle during the second timeframe. As another example, the trend information indicates that the first DT execution module 90 utilizes 75 mA to process a partial task in the first timeframe and utilizes 10 mA when idle during the second timeframe. As yet another example, the trend information indicates that the second DST client module 34 utilizes 110 mA when idle and the third DST client module 34 utilizes 5 mA when idle.

The anomaly detection module 464 detects the anomaly based on the trend information to include comparing recent trend information to historical long-term trend information. In particular, the anomaly may be detected based on an indication that too much power or too little power is being utilized for a current activity of the activity information. As a specific example, the anomaly detection module detects the anomaly as the second DST client module utilizing more power (e.g., more than a power threshold level amount) than the third DST client module 34 when both are idle. When detecting the anomaly, the anomaly detection module issues one or more alerts 478 based on the anomaly. For example, the anomaly detection module 464 issues, via the interface 169, an alert 478 that indicates that the third DST client module 34 is utilizing too much power. As another example, the anomaly detection module 464 issues another alert 478 that indicates that a tenth DT execution module 90 is utilizing too little power when the tenth DT execution module 90 utilizes less power (e.g., by more than another power threshold level amount) than other DT execution modules 90 for a similar activity.

FIG. 12B is a flowchart illustrating an example of detecting a processing activity anomaly. The method continues at step 490 where a processing module (e.g., of an anomaly detection module associated with a distributed storage and task (DST) execution unit) receives power usage information for a plurality of devices with regards to processing activity. The receiving includes one or more of issuing a query, receiving a query response, and receiving an error message. The method continues at step 492 where the processing module receives activity information for the plurality of devices with regards to the processing activity. The receiving includes one or more of issuing a query, receiving a query response, and receiving an error message. The method continues at step 494 where the processing module stores time stamped power usage and activity information to produce a historical record. As a specific example, the processing module obtains a current timestamp and generates the historical record to include the current timestamp and at least some of the power usage and activity information.

The method continues at step 496 where the processing module analyzes historical records to produce trend information. As a specific example, the processing module correlates activity with power usage to produce the trend information (e.g., by types of activities and by power usage by device). The method continues at step 498 where the processing module detects an anomaly of a portion of the processing activity based on the trend information. For example, the processing module, for a current activity, analyzes current power usage for one or more devices and identifies at least one device associated with power usage by activity that compares unfavorably to the trend information (e.g., power consumption too high, power consumption too low).

The method continues at step 500 where the processing module issues an alert based on the detected anomaly. The issuing includes generating the alert to include one or more of a device identifier of the at least one device, a current power usage level of the device, a current activity of the device, and an expected current power usage based on the trend information. The method continues at step 502 where the processing module determines a remedy for the detected anomaly. The determining includes one or more of identifying another device of the plurality devices to perform a task of the at least one device (e.g., selecting another device of the DST execution unit) and identifying another plurality devices where at least one device of the other plurality of devices can perform the task of the at least one device (e.g., selecting another DST execution unit). The method continues at step 504 where the processing module initiates execution of the remedy. As a specific example, the processing module extracts task processing information from the at least one device, sends the task processing information to the identified other device, and instructs the at least one device to cease processing of the task.

FIG. 13A is a schematic block diagram of another embodiment of a dispersed storage network (DSN) that includes the distributed storage and task network (DSTN) managing unit 18 of FIG. 1 and a set of DST execution units 1-n. Each DST execution unit may be implemented utilizing the DST execution unit 36 of FIG. 1. In an example of operation, the DSTN managing unit 18 obtains status information from the set of DST execution units 1-n as status information 1-n. The status information includes one or more of an availability indicator, an active indicator, a required for a rebuilding indicator, a requiring rebuilding indicator, identifiers of DST execution units required for rebuilding, the number of pending data access requests, a number of pending processing requests, and power utilization level information. The obtaining includes at least one of issuing a query, receiving a query response, receiving an error message, receiving an activation chain status response, and accessing a historical record.

The DSTN managing unit 18 selects a DST execution unit associated with an inactive status for reactivation in accordance with a rotation scheme and based on the status information, where a number of remaining DST execution units of the set of DST execution units is greater than or equal to a decode threshold number. The rotation scheme includes at least one of a round-robin scheme, an equal amount of downtime, and an equal amount of uptime. The selecting may be based on one or more of a power utilization level, a desired power utilization level, a number of desired active units, a desired reliability level, a desired availability level, and DST execution unit capabilities.

With the DST execution unit for reactivation selected, the DSTN managing unit 18 issues an activation status change request to the selected DST execution unit. The activation status change request includes one or more of a DST execution unit ID, a requested status (e.g., not active, active), and a status transition approach (e.g., immediately, at a scheduled future timeframe, when no current or pending data access request exists, when no current or pending rebuilding activity exists). As a specific example, the activation status change request includes a request to reactivate and a transition approach for immediate transition (e.g., alternatively for a scheduled transition in accordance with at least one of a transition schedule and a request).

The DSTN managing unit 18 receives a favorable activation status change response from the selected DST execution unit for reactivation. The activation status change response includes one or more of the DST execution unit identifier, the requested status, the actual status, a number of current or pending data access request, a number of current or pending rebuilding task, and an estimated time to status transition when not immediate. As a specific example, the activation status change response includes an indicator that the DST execution unit is now active.

With the DST execution units selected for reactivation now active, the DSTN managing unit 18 selects another DST execution unit associated with an active status for deactivation in accordance with the rotation scheme and based on the status information, where a number of remaining DST execution units of the set of DST execution units is greater than or equal to a decode threshold number. The selecting may be based on one or more of a power utilization level, a desired power utilization level, a number of desired active units, a desired reliability level, a desired availability level, DST execution unit capabilities, and identifying a DST execution unit associated with a number of pending tasks that is less than a low pending tasks threshold level (e.g., few or no pending partial task processing tasks, few or no pending data access tasks).

With the other DST execution units selected for deactivation, the DSTN managing unit 18 determines a transition approach for the other DST execution unit based on the status information (e.g., immediately, scheduled, after pending tasks are executed). As a specific example, the DSTN managing unit 18 determines the transition approach to be the immediate approach when a priority of estimated power savings is greater than all other priorities. As another specific example, the DSTN managing unit 18 determines the transition approach to be after the pending tasks are executed when the pending tasks include critical rebuilding tasks and the critical rebuilding tasks are associated with a priority that is greater than all other priorities. With the transition approach determined, the DSTN managing unit 18 issues and activation status change request to the other DST execution unit, where the activation status change request includes the transition approach and a request to deactivate. The method to change activation status is discussed in greater detail with reference to FIG. 13B.

From time to time, one or more of the DST execution units rebuilds encoded data slices associated with slice errors. The rebuilding includes scanning for errors and remedying the errors. The DST execution units share rebuilding information 510. The rebuilding information 510 includes one or more of a list slice request, a list of slice response, a read slice request, a read slice response, a partial slice request, and the partial slice response. The scanning for errors includes a DST execution unit associated with an active status issuing list slice requests other act of DST execution units and receiving list slice responses for comparison to identify slice errors. The remedying includes an active DST execution unit obtaining at least a decode threshold number of representations of encoded data slices of a set of encoded data slices where at least one encoded data slice is associated with a slice error. The obtaining includes issuing one or more of read slice requests and read partial slice requests to active DST execution units and receiving one or more of read slice responses and read partial slice responses. The obtaining further includes waiting for required DST execution units to become active prior to sending of the one or more of the read slice requests and the read partial slice requests. The method of rebuilding is discussed in greater detail with reference to FIG. 14.

FIG. 13B is a flowchart illustrating an example of selecting active storage units. The method continues at step 512 where a processing module (e.g., of a distributed storage and task network (DSTN) managing unit) obtains status information for a set of storage units. The method continues at step 514 where the processing module selects a storage unit associated with an inactive status for reactivation in accordance with a rotation scheme and based on the status information. As a specific example, the processing module selects a next storage unit of a storage unit rotation list, where the storage unit is associated with an available and inactive status. The method continues at step 516 where the processing module issues and activation status change request to the selected storage unit to reactivate the storage unit. The method continues at step 518 where the processing module receives an activation status change response from the selected storage unit indicating that the storage unit has been reactivated.

When the activation status change response includes a favorable activation status change indicator (e.g., indicating that the selected storage unit has been reactivated), the method continues at step 520 where the processing module selects another storage unit associated with an active status for deactivation in accordance with the rotation scheme and based on the status information. As a specific example, the processing module selects the other storage unit where the other storage unit is associated with no pending storage or rebuilding tasks. The method continues at step 522 where the processing module determines a transition approach for the selected other storage unit based on the status information. As a specific example, the processing module determines the transition approach to include transitioning after pending tasks have been processed when the status information indicates that the other storage unit is associated with pending rebuilding or data access tasks. The method continues at step 524 where the processing module issues and activation status change request to the selected other storage unit, where the request includes the transition approach and an indicator to deactivate the selected other storage unit.

FIG. 14 is a flowchart illustrating an example of enabling slice rebuilding, which includes similar steps to FIG. 13B. The method continues with steps 512-516 of FIG. 13B where a processing module (e.g., of a distributed storage and task network (DSTN) managing unit) obtains status information for a set of storage units, selects a storage unit associated with an inactive status for reactivation in accordance with a rotation scheme and based on the status information, and issues an activation status change request to the selected storage unit.

The method continues at step 526 where the processing module receives an activation status change response from the selected storage unit that indicates detected slice errors and required candidate in active storage units to facilitate rebuilding encoded data slices associated with the detected slice errors. As a specific example, the selected storage unit scans for the slice errors and issues the activation status change response after determining that a decode threshold number of other storage units are not available to facilitate rebuilding.

The method continues at step 528 where the processing module selects one or more other storage units associated with an inactive status for reactivation based on the required candidate in active storage units and in accordance with a rotation scheme. As a specific example, the processing module selects a storage unit that is scheduled for reactivation soon in accordance with the rotation scheme that is included in the required candidate in active storage units. The method continues at step 530 where the processing module issues an activation status change request to the one or more other storage units requesting reactivation.

The method continues with step 518 where the processing module receives an activation status change response from the selected storage unit (e.g., after rebuilding). The method continues at step 532 where the processing module obtains updated status information for the set of storage units. When the activation status change response includes an indication that rebuilding has been completed, the method continues at step 534 where the processing module selects at least one of the one or more other storage units for deactivation in accordance with the rotation scheme and the updated status information. As a specific example, the processing module selects another storage unit where the another storage unit is associated with no pending rebuilding tasks for the selected storage unit.

The method continues at step 536 where the processing module determines a transition approach for the selected at least one storage unit based on the updated status information. As a specific example, the processing module indicates the transition approach to be immediately since rebuilding has been completed for the selected storage unit. As another specific example, the processing module indicates the transition approach to be after processing of the rebuilding tasks associated with other storage units. The method continues at step 538 where the processing module issues an activation status change request of the at least one storage unit, where the request includes the transition approach.

As may be used herein, the terms “substantially” and “approximately” provides an industry-accepted tolerance for its corresponding term and/or relativity between items. Such an industry-accepted tolerance ranges from less than one percent to fifty percent and corresponds to, but is not limited to, component values, integrated circuit process variations, temperature variations, rise and fall times, and/or thermal noise. Such relativity between items ranges from a difference of a few percent to magnitude differences. As may also be used herein, the term(s) “operably coupled to”, “coupled to”, and/or “coupling” includes direct coupling between items and/or indirect coupling between items via an intervening item (e.g., an item includes, but is not limited to, a component, an element, a circuit, and/or a module) where, for indirect coupling, the intervening item does not modify the information of a signal but may adjust its current level, voltage level, and/or power level. As may further be used herein, inferred coupling (i.e., where one element is coupled to another element by inference) includes direct and indirect coupling between two items in the same manner as “coupled to”. As may even further be used herein, the term “operable to” or “operably coupled to” indicates that an item includes one or more of power connections, input(s), output(s), etc., to perform, when activated, one or more its corresponding functions and may further include inferred coupling to one or more other items. As may still further be used herein, the term “associated with”, includes direct and/or indirect coupling of separate items and/or one item being embedded within another item. As may be used herein, the term “compares favorably”, indicates that a comparison between two or more items, signals, etc., provides a desired relationship. For example, when the desired relationship is that signal 1 has a greater magnitude than signal 2, a favorable comparison may be achieved when the magnitude of signal 1 is greater than that of signal 2 or when the magnitude of signal 2 is less than that of signal 1.

As may also be used herein, the terms “processing module”, “processing circuit”, and/or “processing unit” may be a single processing device or a plurality of processing devices. Such a processing device may be a microprocessor, micro-controller, digital signal processor, microcomputer, central processing unit, field programmable gate array, programmable logic device, state machine, logic circuitry, analog circuitry, digital circuitry, and/or any device that manipulates signals (analog and/or digital) based on hard coding of the circuitry and/or operational instructions. The processing module, module, processing circuit, and/or processing unit may be, or further include, memory and/or an integrated memory element, which may be a single memory device, a plurality of memory devices, and/or embedded circuitry of another processing module, module, processing circuit, and/or processing unit. Such a memory device may be a read-only memory, random access memory, volatile memory, non-volatile memory, static memory, dynamic memory, flash memory, cache memory, and/or any device that stores digital information. Note that if the processing module, module, processing circuit, and/or processing unit includes more than one processing device, the processing devices may be centrally located (e.g., directly coupled together via a wired and/or wireless bus structure) or may be distributedly located (e.g., cloud computing via indirect coupling via a local area network and/or a wide area network). Further note that if the processing module, module, processing circuit, and/or processing unit implements one or more of its functions via a state machine, analog circuitry, digital circuitry, and/or logic circuitry, the memory and/or memory element storing the corresponding operational instructions may be embedded within, or external to, the circuitry comprising the state machine, analog circuitry, digital circuitry, and/or logic circuitry. Still further note that, the memory element may store, and the processing module, module, processing circuit, and/or processing unit executes, hard coded and/or operational instructions corresponding to at least some of the steps and/or functions illustrated in one or more of the Figures. Such a memory device or memory element can be included in an article of manufacture.

The present invention has been described above with the aid of method steps illustrating the performance of specified functions and relationships thereof. The boundaries and sequence of these functional building blocks and method steps have been arbitrarily defined herein for convenience of description. Alternate boundaries and sequences can be defined so long as the specified functions and relationships are appropriately performed. Any such alternate boundaries or sequences are thus within the scope and spirit of the claimed invention. Further, the boundaries of these functional building blocks have been arbitrarily defined for convenience of description. Alternate boundaries could be defined as long as the certain significant functions are appropriately performed. Similarly, flow diagram blocks may also have been arbitrarily defined herein to illustrate certain significant functionality. To the extent used, the flow diagram block boundaries and sequence could have been defined otherwise and still perform the certain significant functionality. Such alternate definitions of both functional building blocks and flow diagram blocks and sequences are thus within the scope and spirit of the claimed invention. One of average skill in the art will also recognize that the functional building blocks, and other illustrative blocks, modules and components herein, can be implemented as illustrated or by discrete components, application specific integrated circuits, processors executing appropriate software and the like or any combination thereof.

The present invention may have also been described, at least in part, in terms of one or more embodiments. An embodiment of the present invention is used herein to illustrate the present invention, an aspect thereof, a feature thereof, a concept thereof, and/or an example thereof. A physical embodiment of an apparatus, an article of manufacture, a machine, and/or of a process that embodies the present invention may include one or more of the aspects, features, concepts, examples, etc. described with reference to one or more of the embodiments discussed herein. Further, from figure to figure, the embodiments may incorporate the same or similarly named functions, steps, modules, etc. that may use the same or different reference numbers and, as such, the functions, steps, modules, etc. may be the same or similar functions, steps, modules, etc. or different ones.

While the transistors in the above described figure(s) is/are shown as field effect transistors (FETs), as one of ordinary skill in the art will appreciate, the transistors may be implemented using any type of transistor structure including, but not limited to, bipolar, metal oxide semiconductor field effect transistors (MOSFET), N-well transistors, P-well transistors, enhancement mode, depletion mode, and zero voltage threshold (VT) transistors.

Unless specifically stated to the contra, signals to, from, and/or between elements in a figure of any of the figures presented herein may be analog or digital, continuous time or discrete time, and single-ended or differential. For instance, if a signal path is shown as a single-ended path, it also represents a differential signal path. Similarly, if a signal path is shown as a differential path, it also represents a single-ended signal path. While one or more particular architectures are described herein, other architectures can likewise be implemented that use one or more data buses not expressly shown, direct connectivity between elements, and/or indirect coupling between other elements as recognized by one of average skill in the art.

The term “module” is used in the description of the various embodiments of the present invention. A module includes a processing module, a functional block, hardware, and/or software stored on memory for performing one or more functions as may be described herein. Note that, if the module is implemented via hardware, the hardware may operate independently and/or in conjunction software and/or firmware. As used herein, a module may contain one or more sub-modules, each of which may be one or more modules.

While particular combinations of various functions and features of the present invention have been expressly described herein, other combinations of these features and functions are likewise possible. The present invention is not limited by the particular examples disclosed herein and expressly incorporates these other combinations. 

What is claimed is:
 1. A method for execution by one or more processing modules of one or more computing devices of a dispersed storage network (DSN), the method comprises: obtaining status information from a set of distributed storage units; determining that a plurality of distributed storage units of the set of distributed storage units are associated with an inactive status; selecting a first distributed storage unit of the plurality of distributed storage associated with an inactive status for reactivation; issuing a request to change activation status to the first distributed storage unit; receiving a favorable response to the request to change activation status from the first distributed storage unit; determining that the favorable response from the first distributed storage unit includes an indication that one or more dispersal storage encoded data slices stored in the first distributed storage unit include one or more errors; determining to facilitate rebuilding the one or more dispersal storage encoded data slices stored in the first distributed storage unit that include one or more errors; selecting a second distributed storage unit of the plurality of distributed storage associated with an inactive status for reactivation, wherein the second distributed storage unit includes dispersal storage encoded data slices required to rebuild the dispersal storage encoded data slices stored in the first distributed storage unit that include one or more errors; issuing a request to change activation status to the second distributed storage unit; receiving a favorable response to the request to change activation status; rebuilding one or more dispersal storage encoded data slices stored in the first distributed storage unit using dispersal storage encoded data slices from the second distributed storage unit; obtaining updated status information from the set of distributed storage units; and based on the updated status information, determining to transition one or more distributed storage units of the set of distributed storage units to inactive status.
 2. The method of claim 1, wherein the status information includes at least one of: an availability indicator; an activity indicator; a required for a rebuilding indicator; a requiring rebuilding indicator; one or more identifiers of DST execution units required for rebuilding; a number of pending data access requests; a number of pending processing requests; or information sufficient to determine a power utilization level.
 3. The method of claim 1, wherein obtaining status information from the set of distributed storage units includes at least one of issuing a query, receiving a query response, receiving an error message, receiving an activation chain status response, and accessing a historical record.
 4. The method of claim 1, wherein the selecting a first distributed storage unit of the plurality of distributed storage associated with an inactive status for reactivation is based at least partially on a rotation scheme.
 5. The method of claim 4, wherein the rotation scheme includes at least one of a round-robin scheme, a predetermined amount of downtime and a predetermined amount of uptime.
 6. The method of claim 1, wherein the request to change activation status includes at least one of a distributed storage execution unit identifier, a requested activity status and a status transition approach.
 7. The method of claim 1, wherein the determining to transition one or more distributed storage units of the set of distributed storage units to inactive status is further based on a transition approach, wherein the transition approach is at least one of transitioning after pending tasks have been processed, transitioning immediately after rebuilding the one or more dispersal storage encoded data slices stored in the first distributed storage unit and transitioning according to a rotation scheme.
 8. The method of claim 1, wherein the determining to transition one or more distributed storage units of the set of distributed storage units to inactive status includes: selecting the one or more distributed storage units of the set of distributed storage units to transition to inactive status based on at least one of: a power utilization level; a desired power utilization level; a number of desired active units; a desired reliability level; a desired availability level; distributed storage unit capabilities; or identifying a distributed storage unit associated with a number of pending tasks that is less than a low pending tasks threshold level.
 9. A dispersed storage and task (DST) processing unit comprises: at least one module, when operable within a computing device, that causes the computing device to: obtain status information from a set of distributed storage units; determine that a plurality of distributed storage units of the set of distributed storage units are associated with an inactive status; select a first distributed storage unit of the plurality of distributed storage associated with an inactive status for reactivation; issue a request to change activation status to the first distributed storage unit; receive a favorable response to the request to change activation status from the first distributed storage unit; determine that the favorable response from the first distributed storage unit includes an indication that one or more dispersal storage encoded data slices stored in the first distributed storage unit include one or more errors; determine to facilitate rebuilding the one or more dispersal storage encoded data slices stored in the first distributed storage unit that include one or more errors; select a second distributed storage unit of the plurality of distributed storage associated with an inactive status for reactivation, wherein the second distributed storage unit includes dispersal storage encoded data slices required to rebuild the dispersal storage encoded data slices stored in the first distributed storage unit that include one or more errors; issue a request to change activation status to the second distributed storage unit; receive a favorable response to the request to change activation status; rebuild one or more dispersal storage encoded data slices stored in the first distributed storage unit using dispersal storage encoded data slices from the second distributed storage unit; obtain updated status information from the set of distributed storage units; and based on the updated status information, determine to transition one or more distributed storage units of the set of distributed storage units to inactive status.
 10. The DST processing unit of claim 9, wherein the status information comprises at least one of: an availability indicator; an activity indicator; a required for a rebuilding indicator; a requiring rebuilding indicator; one or more identifiers of DST execution units required for rebuilding; a number of pending data access requests; a number of pending processing requests; and information sufficient to determine a power utilization level.
 11. The DST processing unit of claim 9, wherein the at least one module, when operable within a computing device, further causes the computing device to: obtain status information from the set of distributed storage units based on at least one of: issuing a query; receiving a query response; receiving an error message; receiving an activation chain status response; and accessing a historical record.
 12. The DST processing unit of claim 9, wherein the at least one module, when operable within a computing device, further causes the computing device to: select a first distributed storage unit of the plurality of distributed storage associated with an inactive status for reactivation based at least partially on a rotation scheme.
 13. The DST processing unit of claim 9, wherein the at least one module, when operable within a computing device, further causes the computing device to: determine to transition one or more distributed storage units of the set of distributed storage units to inactive status based on a transition approach, wherein the transition approach is at least one of transitioning after pending tasks have been processed, transitioning immediately after rebuilding the one or more dispersal storage encoded data slices stored in the first distributed storage unit and transitioning according to a rotation scheme.
 14. The DST processing unit of claim 9, wherein the at least one module, when operable within a computing device, further causes the computing device to: determine to transition one or more distributed storage units of the set of distributed storage units to inactive status based on a transition approach, wherein the transition approach is at least one of transitioning after pending tasks have been processed, transitioning immediately after rebuilding the one or more dispersal storage encoded data slices stored in the first distributed storage unit and transitioning according to a rotation scheme.
 15. The DST processing unit of claim 9, wherein the at least one module, when operable within a computing device, further causes the computing device to: select the one or more distributed storage units of the set of distributed storage units to transition to inactive status based on at least one of: a power utilization level; a desired power utilization level; a number of desired active units; a desired reliability level; a desired availability level; distributed storage unit capabilities; or identifying a distributed storage unit associated with a number of pending tasks that is less than a low pending tasks threshold level.
 16. A computer readable storage medium comprises: at least one memory section that stores operational instructions that, when executed by one or more processing modules of one or more computing devices of a dispersed storage network (DSN), causes the one or more computing devices to: obtain status information from a set of distributed storage units; determine that a plurality of distributed storage units of the set of distributed storage units are associated with an inactive status; select a first distributed storage unit of the plurality of distributed storage associated with an inactive status for reactivation; issue a request to change activation status to the first distributed storage unit; receive a favorable response to the request to change activation status from the first distributed storage unit; determine that the favorable response from the first distributed storage unit includes an indication that one or more dispersal storage encoded data slices stored in the first distributed storage unit include one or more errors; determine to facilitate rebuilding the one or more dispersal storage encoded data slices stored in the first distributed storage unit that include one or more errors; select a second distributed storage unit of the plurality of distributed storage associated with an inactive status for reactivation, wherein the second distributed storage unit includes dispersal storage encoded data slices required to rebuild the dispersal storage encoded data slices stored in the first distributed storage unit that include one or more errors; issue a request to change activation status to the second distributed storage unit; receive a favorable response to the request to change activation status; rebuild one or more dispersal storage encoded data slices stored in the first distributed storage unit using dispersal storage encoded data slices from the second distributed storage unit; obtain updated status information from the set of distributed storage units; and based on the updated status information, determine to transition one or more distributed storage units of the set of distributed storage units to inactive status.
 17. The computer readable storage medium of claim 16, status information comprises at least one of: an availability indicator; an activity indicator; a required for a rebuilding indicator; a requiring rebuilding indicator; one or more identifiers of DST execution units required for rebuilding; a number of pending data access requests; a number of pending processing requests; and information sufficient to determine a power utilization level.
 18. The computer readable storage medium of claim 16, wherein the at least one memory section further causes the one or more computing devices to: obtain status information from the set of distributed storage units based on at least one of: issuing a query; receiving a query response; receiving an error message; receiving an activation chain status response; and accessing a historical record.
 19. The computer readable storage medium of claim 16, wherein the at least one memory section further causes the one or more computing devices to: determine to transition one or more distributed storage units of the set of distributed storage units to inactive status based on a transition approach, wherein the transition approach is at least one of transitioning after pending tasks have been processed, transitioning immediately after rebuilding the one or more dispersal storage encoded data slices stored in the first distributed storage unit and transitioning according to a rotation scheme.
 20. The computer readable storage medium of claim 16, wherein the at least one memory section further causes the one or more computing devices to: select the one or more distributed storage units of the set of distributed storage units to transition to inactive status based on at least one of: a power utilization level; a desired power utilization level; a number of desired active units; a desired reliability level; a desired availability level; distributed storage unit capabilities; or identifying a distributed storage unit associated with a number of pending tasks that is less than a low pending tasks threshold level. 